Azure Database for PostgreSQL – Flexible Server now supports zone redundant high availability in more regions: including Central India, Korea Central, East Asia, and West US 3. You can now deploy your new servers in these regions with zone redundant high availability (HA) mode that provides availability zone (AZ) level resiliency.
If you have already provisioned servers in these regions and the provisioned availability zone shows as “no preference” in the high availability blade, you cannot directly convert servers to zone-redundant high availability servers. In these cases, please read the documentation to learn about options for converting to high availability mode.